Releasable microcapsules on balloon catheters

Abstract

Balloon catheters are prepared to include body affecting chemicals within microcapsules on the exterior of the balloon either alone or with a stent. The coating releases from the balloon when the balloon is inflated into contact with the lumen to be treated. The device provides accurate placement of the dosage required at the location in need of treatment. A sheath may be employed over the balloon and microcapsules to prevent the microcapsules from being rubbed off during delivery through a body lumen. The catheters are especially useful in balloon angioplasty procedures.

What is claimed: 
     
       1. In a catheter of the type comprising a catheter body and a balloon positioned along the length of the catheter body, said catheter including means for remotely inflating and deflating said balloon; the improvement comprising: a. a plurality of microcapsules applied to the exterior of said balloon, each of said microcapsules carrying a drug or combination of drugs for treatment or diagnostics within a body lumen wherein the microcapsules are attached to the balloon by an adhesive which stretches and ruptures the microcapsules as the balloon expands; and   b. a stent on the exterior of said balloon, the stent comprising a plurality of elements forming a hollow cylinder, the elements spaced apart along the cylinder with each of the elements extending around the cylinder, and each of the elements having zig-zags therein taking a generally longitudinal direction along the cylinder and then reversing their direction and lying flat with respect to the cylinder such that the zig-zags open as the stent is expanded from a first diameter to a second, expanded diameter, exposing the balloon and applied microcapsules on the balloon between the elements for direct contact with a body lumen.   
     
     
       2. In a catheter of the type comprising a catheter body and a balloon positioned along the length of the catheter body, said catheter including means for remotely inflating and deflating said balloon; the improvement comprising: a. a plurality of microcapsules applied to the exterior of said balloon, each of said microcapsules carrying a drug or combination of drugs for treatment or diagnostics within a body lumen which rupture under applied pressure to release the drug or combination of drugs for treatment or diagnostics wherein the microcapsules are attached to the balloon by an adhesive which stretches and ruptures the microcapsules as the balloon expands; and   b. a stent on the exterior of said balloon, the stent comprising a plurality of elements forming a hollow cylinder and which open as the stent is expanded from a first diameter to a second, expanded diameter, exposing the balloon and applied microcapsules on the balloon between the elements for direct contact with a body lumen.